URUMQI, China, May 2 (Reuters) - China's foreign ministry has reacted angrily to U.S. criticism of the level of cooperation from Beijing on fighting terrorism, after an apparent suicide bombing in the country's far west pointed to a possible escalation of unrest there.

The Chinese government has blamed religious extremists for carrying out a bomb and knife attack at a train station in Urumqi, regional capital of Xinjiang, on Wednesday evening that killed one bystander and wounded 79.

Security was heavy on Friday in Urumqi, scene of deadly riots five years ago between Muslim Uighurs and ethnic Han Chinese in which almost 200 were killed.

The train station was bustling, with hundreds of migrant workers arriving from around China for seasonal work. Many sat on their bags in the station plaza waiting for trains to other parts of the region.

Units of armed police carrying assault rifles and sharpened black metal poles with hand grips marched in file around the station grounds. Black police vans and armoured troop transports were parked in front of the station's entrance.

Resource-rich and strategically located Xinjiang, on the borders of central Asia, has for years been beset by violence blamed by the Chinese government on Islamist militants and separatists, but suicide attacks have been extremely rare.

"China falls victim of terrorism, and always firmly opposes terrorism in any form and terrorist acts conducted or backed by any person under any name," the foreign ministry said in a statement late on Thursday.

Beijing is unhappy at the U.S. State Department's 2013 country reports on terrorism, published last month, which said China's cooperation on fighting terrorism "remained marginal" and that the Chinese provided scarce evidence to prove terrorist involvement in incidents in Xinjiang.

"On the issue of fighting terrorism, to make irresponsible remarks towards other countries and adopting double standards will not help international cooperation on counter-terrorism," The foreign ministry said.

Xinjiang's regional government said on its official news website on Thursday that the Urumqi attack had been carried out by two men who had "long been influenced by extremist religious thought and participated in extremist religious activities".

Both were killed in the blast, it said. It identified one of them as Sedirdin Sawut, a 39-year-old man from Xayar county in Xinjiang's Aksu region. The man is a member of the Muslim Uighur minority, judging by his name.

There have been suicide bombings before in China, mostly by people with personal grievances, but it has generally not been a tactic employed by Uighurs.

In October, a car ploughed into tourists on the edge of Beijing's Tiananmen Square, killing the car's three occupants and two bystanders, in what the government believed was a suicide attack by people from Xinjiang.

ETHNIC TENSIONS

Exiles and many rights groups say the real cause of the unrest in Xinjiang is China's heavy-handed policies, including curbs on Islam and the culture and language of the Uighur people.

Urumqi is heavily populated by Han Chinese, who have flooded there seeking business opportunities. Uighurs have complained that they have been frozen out of the job market. Many were reluctant to talk to reporters.

"I just don't believe it was a Uighur who did this," one 35-year-old Uighur man selling dried fruit about 100 metres from the blast site told Reuters on Thursday. "These public spaces aren't safe for anyone, Uighur or Han."

Accounts of Wednesday's attack have come mostly from China's heavily censored state media. Independent reporting in Xinjiang is extremely difficult due to the tight security and wariness many Uighurs have at talking to foreign reporters.

The Xinhua news agency cited police as saying "knife-wielding mobs" slashed at people at an exit of the station and set off explosives.

The bombing, the first in Urumqi in 17 years, was possibly timed to coincide with a visit to the region with a large Muslim minority by President Xi Jinping. State media did not say whether Xi was anywhere near Urumqi at the time.

The government called the attackers "terrorists", a term it uses to describe Islamist militants and separatists in Xinjiang who have waged a sometimes violent campaign for an independent East Turkestan state.

In Washington, the State Department also said all signs pointed to the attack being the work of terrorists.

"Based on the information we have seen, including what has been reported by the Chinese media, this appears to be an act of terrorism that targets random members of the public," State Department spokeswoman Marie Harf told a daily briefing.

Thursday's foreign ministry statement said China has always sought to combat terrorism in accordance with law while paying attention to "eliminating both the symptoms and root causes of terrorism", adding that China opposed "linking terrorism to specific ethnic groups or religions".

The station bombing was the largest militant attack in Urumqi since the government blamed Uighurs for stabbing hundreds of Han Chinese with needles in 2009. No one was killed in that incident.

Unrest in Xinjiang has caused the deaths of more than 100 people in the past year, prompting a tougher stance against the Turkic-language speaking Uighurs, many of whom resent government controls on their culture and religion.

In March, 29 people were stabbed to death in the southwestern city of Kunming, far from Xinjiang and on the borders of Southeast Asia. The government blamed that attack on Xinjiang extremists. (Additional reporting by Ben Blanchard in Beijing; Editing by Alex Richardson)

After bombing in west, China angered by U.S. criticism in terror report

We welcome comments that advance the story through relevant opinion, anecdotes, links and data. If you see a comment that you believe is irrelevant or inappropriate, you can flag it to our editors by using the report abuse links. Views expressed in the comments do not represent those of the Thomson Reuters Foundation. For more information see our Acceptable Use Policy.